Lamp grip



M. N. RussE'LL LAMP GRI P Filed March 7, 1925 Patented Oct. 4, 1927.

oNirED` fsTATEs v o 1,644,038 PATE-NT f MARK N. RUssELL, OF sYnAoUsE; NEW YORK7 As'SIGNORV 'ro Less: a sEYMOR, INC., OF

y sYnAOUsE, NEW YORK, A CORPORATION OF NEW YORK.

AMP GRIP.

np-piicaon filed-March 7, 1925.-yy serial No; v13,912.

Thisinvention relates to sookets for incandescent lamps or for fuses or like Objects which are threa'ded into the screw shell 'of the socket which forms 'one of the electrical terminale.

It is a general object of this invention to provide in a screw shell socket a 'novel and improved means for reta'ining lamps or the like therein in a more positive manner. I,

Moro particularly it is an obj ect of this 1nvention to provide a friction device or lamp of the present invention with the under-.

standing, however, that lvarious mo'difications and changes may be made in Vthe size, form, proportion, material and arrangement of the various parts without departing from the scope of the attached claim.

T11 said drawings Figure 1 is a side elevation partially in central longitudinal section hrough a socket constructed according to this invent-ion.

Figure 2 is a transverse section through the screw shell of the socket, and

Figure 3 is a l-Ongitudinal central section through the screw shell taken in a plane at right angles to that shown in Figure 1.

In using the ordinary form of screw socket for lamps, fuses, attachment plugs and other similar devices, it has beenpfound that there is sometimes a tendency for the lamp or other object to become loosened so that the electrical contact betweenV the center button on the base of the lamp and the center contact of the socket is very poor or entirely broken. In the former case, arcing or heating of the respective parts may result, whereas in thelatter case the circuit to the lamp Or other object is Open and it will not Operate. This condition is exaggerated where the socket and its associated part is subject to considerable vbration such as in tall buildings or around machinery, on street cars, etc. The use of socket switches of the various types may also aggravate this condition and it therefore has been found desirable to provide some means to more V in loosening the base thereof.

securely retain lthe' lamp 'Or the like within the s'ocketfandV yet which, at the sameItime, will'not nece'ssitate an undue twist being given the lamp or tlielike'which may result The device of the presentfinventi'on Vhas beendesigned to overcome these difiiculties in an extremely simple' m'anner.

Referring' to the drawings, there is shown inlFigure 1 a' comin'onform of incandescent lamp socket including the outer sliell 10, the cap fll, the insulating button' 12, the Vin'- sulating llining 13, the screw shell 14 land the center'contact 15,-all` of which are wellknown. Any form of socket switch' may be provided if 'desir'ecl V`At 16is shown an incan'd'escent'lamp ha'vingthelthreadedbase 1'7 and'rthe center-contact 18 yi-nsulat'ed therefrom.` The base 17 ofthe lamp is usuallyso proportioned as' tofiti looselywithin' the t'hreaded shell 14 of the socket, Vrelian'ce vbeingi 'placed 'upon the'frictional engagement of the respective threads with eachl Other, due to the contact between the parts 15 and 18 to retain the lamp in position. In Order that this frictional engagement may be sufii- 'cient to prevent the lamp from jarring loose and thus reducing the eifectiveness Vof the electrical contact between the parts-15 and 18, it is necessary that the lamp be screwed quite tightly into the socket, which may result in breaking the shell 17 loose from the lamp 16, since the connection between these two parts is efiected by a cement. Such loosening of the threaded Shell from the lamp may render it useless, vsince a subscquent twist Of the lamp in respect to the shell 'may twist the two lead wires within the base and short-Circuit them. V

The present invention contemplates Overcoming these difliculties by providing the grip member 19 which is attached to the inner face of the screw shell 14 by means of the tabs or ears 20 formed -integral' with the grip member and bent over the ends of the screw shell 14. This grip member`19 comprises, merely, a narrow rectangular strip of spring metal slightly bowed to expose its convex face for contact with the tops of the threads On the lamp base 17.l

To provide'accommodation ,for this grip member 19 the screw shell 14 which is formed of quite thin metal, rolled Or pressed into the threaded form shown, is provided with a longitudinal channel 21 pressed into eov screw shell.

'its inner face to such a depth as to receive the grip member 19 with its inner surface, When in al flattene'd or non-bowed condition, slightly above the bottoms of the threads in the screwV shell 14. This is clearly 'shown in Figure 2 which is a section transverse to the screw shell taken near the middle of the grip member, and it will be noticed that the center portion of the grip member is bowed outward toward the center of the screw shell so as to more readily engage the tops of the threads on the lamp base in spite of slight variations in the size of the bases made by different manufacturers.

In using the device it provides an easy but positively frictional engagement between the threads of the 'lamp base 17 and those of the screW vshell lt by foreing the side of the base remote from the grip memher against the opposite inner wall of the At the same time the grip member provides adequate frictional engagement with the tops of the threads on the lamp base 17, which, if it is large enough, presses on the central bowed portion of the grip and fiattens it down into the channel .21 made to receive it. The walls 22 of the channel 21 engage with the edges of the grip member 19 and prevent it from being rotated in either direction when the lamp is beingplaced in or removed from the socket and the lend tabs 20, loosely bent over the ends of the shell, prevent any longitudinal movement of the grip member.

It has been the usual vpractice to make the center contact 15 resilient or in the form of some sort of spring, in order' that it may be partially compressed when the lamp is screw'ed into the socket so that in case any vibration lo'osens the lamp this spring contact will follow the center button 18 on the lamp for some. distance and still remain in contact with it. i With the present construction, however, it is possible to eliminate the spring from the center contact 15 since the lamp grip means serves to positively retain the 'center contact of the lamp against the center contact of the socletf This results in a cheaper construction, since it is not necessary to use expensive spring` material or as complicated a structure for a solid center contact as for a spring contact, and furthermore there is even less possibility of loosening at this point.

Having thus described my invention, what is claimed as new and desired to be secured w MARK N. RSSELL. 

